Eeek, wish I had seen this thread earlier. Hey there, creator of XYscope here and happy to see its use start to popup. Thanks everyone above for the clarification on physical setup that I've completely forgotten to include on the library documentation (tunnel vision on project)...

Yup relying heavily on Minim for converting the vector shapes to audio waves that are sent via plane ol stereo to the X - Y inputs of a scope in XY mode. You can use the headphone jack, with a 1/8" minijack to RCA/cinch cable.. attaching to the oscilloscope with BNC to RCA/cinch adaptors. Those cables/adaptors would be just a few dollars. Eventually, you may want to get a multi-channel DAC for not only controlling multiple oscilloscopes, but also getting 3 channels out, for XY and Z (blanking/brightness) for even more fun.